England captain Nat Sciver-Brunt has been passed fit for Thursday's T20 World Cup semi-final against South Africa, after a lot of work behind the scenes.

The all-rounder used many well-known techniques to aid her recovery - ice, compression, physio treatment and oxygen therapy - but also one never used before by the women's cricket team. Sciver-Brunt underwent magnetic resonance therapy, an uncommon treatment sometimes called MBST. It uses electromagnetic energy to encourage cell healing and is more regularly used to treat arthritis.

The 33-year-old had seven hour-long sessions "sitting and not moving with my leg in a horseshoe-shaped thing", saying she "threw everything at" getting fit again.

While the treatment is uncommon, legendary former NBA player Shaquille O'Neal has spoken about using similar treatments. Sciver-Brunt had the machine with her at home and in the team hotel.

Nick Worth, a sports and performance physiotherapist who has worked with elite athletes for 30 years, said while evidence is limited there have been examples of positive results. "The electromagnetic field goes around the injured area and they have treatment for about an hour seven or eight times," he told BBC Sport.

"The electromagnetic energy has an impact on the cells that promotes healing in the cells naturally, rather than it needing any medication or drugs. The main thing is it is a safe option. It isn't going to do any harm.

"It is not the kind of treatment that is commonly used, but in elite sport you are trying to push the boundaries to find something that would give a small amount of benefit. It is one of those things that seems to have some benefit but it is difficult being able to definitely confirm it is."

Larger magnetic resonance therapy machines can be used to treat issues such as arthritis.

Sciver-Brunt first injured her calf on 29 April, suffering what was then described by England as a "minor" tear when playing in domestic cricket. She subsequently sat out the series against New Zealand and then India at the start of the international summer, before returning for England's World Cup warm-up matches.

The England skipper came through warm-ups against Australia and India and the first match of the World Cup against Sri Lanka but reported 'tightness' in a win over Ireland 10 days ago. She batted in the nets on Friday, Tuesday and Wednesday, but has not been seen doing more than a gentle run otherwise.

Worth suggested the nature of cricket means it is very difficult to replicate match situations while completing rehabilitation for calf injuries. "Things like taking a run, going from 0 to 100mph, are really difficult to replicate," he added.

"You have the immediate calming down on inflammation but tendons like load and need to strengthen. It is very difficult to get the balance between working the muscle enough and not pushing it too far. Quite often calf injuries are tricky because you feel like you have done the work and you put them back onto the field in a match situation and something goes again."